X0508 4 2024-08-29 0000944695 HANOVER INSURANCE GROUP, INC. THG 0001275977 LAVEY RICHARD W C/O THE HANOVER INSURANCE GROUP, INC. 440 LINCOLN STREET WORCESTER MA 01653 0 1 0 0 Executive Vice President 1 Common Stock 2024-08-29 4 M 0 8468 66.140 A 44748.900 D Common Stock 2024-08-29 4 S 0 8468 144.01 D 36280.900 D Common Stock 2024-08-30 4 M 0 3358 66.140 A 39638.900 D Common Stock 2024-08-30 4 S 0 1950 144.58 D 37688.900 D Common Stock 2024-08-30 4 S 0 1243 145.41 D 36445.900 D Common Stock 2024-08-30 4 S 0 165 146.48 D 36280.900 D Common Stock Option (right to buy) 66.140 2024-08-29 4 M 0 8468 0 D 2025-02-27 Common Stock 8468 3358 D Common Stock Option (right to buy) 66.140 2024-08-30 4 M 0 3358 0 D 2025-02-27 Common Stock 3358 0 D Exercise of options scheduled to expire in February 2025 and resulting sale of shares reported were effected pursuant to a pre-established Rule 10b5-1 Trading Plan. The price reported in Column 4 is a weighted average price. The shares were sold at multiple prices ranging from $144 to $144.05. The Reporting Person undertakes to provide The Hanover Insurance Group, Inc. ("THG"), any security holder of THG, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range set forth above. The price reported in Column 4 is a weighted average price. The shares were sold at multiple prices ranging from $144.02 to $144.87. The Reporting Person undertakes to provide THG, any security holder of THG, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range set forth above. The price reported in Column 4 is a weighted average price. The shares were sold at multiple prices ranging from $145.09 to $145.65. The Reporting Person undertakes to provide THG, any security holder of THG, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range set forth above. The price reported in Column 4 is a weighted average price. The shares were sold at multiple prices ranging from $146.18 to $146.82. The Reporting Person undertakes to provide THG, any security holder of THG, or the staff of the SEC, upon request, full information regarding the number of shares sold at each separate price within the range set forth above. The option, representing the right to purchase a total of 17,738 shares, vested 1/3 on each of 2/27/16, 2/27/17 and 2/27/18. /s/ Lindsay L. Katz pursuant to Confirming Statement 2024-09-03